Conveyor devices with traction elements are used, in particular, for transporting loose conveyed material, such as bulk piece goods. For this purpose, the conveyor devices have traction elements, in particular flat belts, warp knit fabrics or the like which carry the conveyed material or acts on it or picks it up. The traction element is guided or deflected by way of rollers.
Such conveyor devices are used, for example, in agricultural round balers which pick up straw or hay as the conveyed material, in order to wind the material into the shape of a round bale.
In particular in round balers, it is necessary to feed the conveyed material uniformly, since the external shape of the round bale is dependent upon the uniformity of feeding of the material to be pressed.
When the conveyed material is fed in a non-uniform way, the traction element is loaded on one side. In addition to the movement component in the running direction of the traction element, one-sided loading also results in a movement component which runs transversely with respect to the direction of movement and by which the traction element is moved on the roller in the direction of the rotational axis thereof. This oblique running of the traction element can lead to tearing of the traction element or to crossing over of adjoining traction elements which run parallel to one another.
In order to avoid oblique running of the traction elements it is known from the prior art to arrange, at the side edges of the traction elements, guide strips which extend in a direction parallel to the running direction of the traction elements and prevent a movement of the traction elements which are directed transversely with respect to the latter.
Owing to the friction between the side edge of the traction elements and the guide strip, the traction elements are subject to more rapid wear than would be the case without the guide strips. Furthermore, guide strips also generally constitute collecting points for circulating conveyed material, and this can lead to blockages.